As a method for removing particles adhering to the surface of a semiconductor substrate, brush cleaning may be employed. In the brush cleaning, particles are removed by a combination of lift-off action, electrical repulsion and the like of a cleaning solution and physical action by friction of a brush.
In the conventional brush cleaning of a semiconductor substrate, a semiconductor substrate is driven and rotated while a brush is moved along the surface of the substrate with a cleaning solution supplied onto the surface of the substrate. Particularly, in recent years, a brush cleaning mechanism is incorporated in a CMP (Chemical Mechanical Polishing) system in some cases so as to be used for removing abrasive grain in a polishing solution and polishing dust and the like generated by polishing.
As a typical surface treating machine that performs the brush cleaning, there are known in general a semiconductor substrate cleaning machine using a cup-shaped (disk-shaped) blush shown in FIG. 27 and a semiconductor substrate cleaning machine using a cylindrical (roll) blush shown in FIG. 28.
In the semiconductor substrate cleaning machine using the cup-shaped blush shown in FIG. 27, a semiconductor substrate 11 is held by a vacuum chuck or an edge chuck (not shown) and is rotated, and a brush 12 removes particles 17 from the semiconductor substrate 11. The brush 12 is mounted at a cup-shaped (disk-shaped) jig 13, and an arm 15 connected to the jig 13 sweeps the surface of the semiconductor substrate 11. During sweeping, a cleaning solution 14 is supplied onto the surface of the semiconductor substrate 11 from a nozzle 16 for surface treatment in combination with brushing by the brush 12 and action of the cleaning solution 14. The brush 12 is made of nylon, PVA (polyvinylalcohol), or the like usually.
On the other hand, in the cleaning machine using the cylindrical brush shown in FIG. 28, a brush 22 performs treatment for removing particles 26 from the surface of a semiconductor substrate 21 held and rotated similarly to that in the cleaning machine using the cup-shaped brush in FIG. 27. The blush 22 is provided radially around the outer periphery of a cylindrical brush support member 23 so as press the surface of the semiconductor substrate 21 while being rotated by rotation of the blush support member 23. During rotation, a cleaning solution 24 is supplied onto the surface of the semiconductor substrate 21 from the nozzle 25, thereby performing the surface treatment. The brush 12 is made of nylon, PVA (polyvinylalcohol), or the like usually, similarly.
In both the cleaning machine using the cup-shaped brush and the cleaning machine using the cylindrical brush, a cleaning step as depicted in FIG. 29 is performed. The brush is positioned apart from the semiconductor substrate in a standby state before cleaning. Cleaning is performed for a predetermined time period in such a manner that the rotated brush is pressed against the rotated semiconductor substrate at a given high pressing pressure (for example, about 50 g/cm2 as pressure of the brush in contact with the surface of the semiconductor substrate is applied to the semiconductor substrate) while the cleaning solution is supplied. Thereafter, when the cleaning is terminated, the blush is moved away from the semiconductor substrate to be in the standby state. In general, cleaning solution supply is stopped concurrently with separation of the brush from the semiconductor substrate.
Japanese Patent No. 3140520(2) is listed as a patent document in this art.